• APL (programming language), a computer programming language with specialized array processing capabilities
• Above Poverty Line, the section of people who can fulfil their minimum basic needs
• Acute promyelocytic leukemia, a subtype of acute myelogenous leukemia
• Acting Patrol Leader
• apl.de.ap, pseudonym of Allan Pineda Lindo, a member of hip hop group The Black Eyed Peas
• AMD Performance Library, a compiler library for AMD multi-threaded processors
• American President Lines, a Singapore-based container transportation and shipping company
• American Protective League, a WWI era pro-war organization
• apl, file extension of the Monkey's Audio metadata file
• APL, United States Navy hull classification symbol for Barracks Craft
• Applied Physics Letters, journal published by American Institute of Physics
• Applied Physics Laboratory, Johns Hopkins University
• Assistant Patrol Leader
• Association of Pension Lawyers
• Australian Poker League, offers free poker in pubs and clubs
• Australian Premier League, an online football gaming league
• Average Picture Level, a Federal Standard 1037C terms
• Nampula Airport, Mozambique, from its IATA airport code
• several software licenses, including:
• Adaptive Public License
• AROS Public License, license of AROS Research Operating System, formerly Amiga Research Operating System
• Arphic Public License, license of freely available fonts for East Asian codepages on Enabling East Asian characters#Debian GNU/Linux
• Irish Anti-Partition League

Furthermore, APL is the name of an asteroid: 132524 APL